Submitted 3 June 2014Accepted 7 August 2014Published 28 August 2014

Corresponding authorRobert Johansson,robert.johansson@liu.se

Academic editorEllen Hodnett

Additional Information andDeclarations can be found onpage 17

DOI 10.7717/peerj.548

Copyright2014 Johansson et al.

Distributed underCreative Commons CC-BY 4.0

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Davanloo’s Intensive Short-TermDynamic Psychotherapy in a tertiarypsychotherapy service: overalleffectiveness and association betweenunlocking the unconscious and outcomeRobert Johansson1,2, Joel M. Town1 and Allan Abbass1

1 Centre for Emotions and Health, Dalhousie University, Halifax, Nova Scotia, Canada2 Department of Behavioural Sciences and Learning, Linkoping University, Linkoping, Sweden

ABSTRACTBackground. Intensive Short-Term Dynamic Psychotherapy (ISTDP), as developedby Habib Davanloo, is an intensive emotion-focused psychodynamic therapy withan explicit focus on handling resistance in treatment. A core assumption in ISTDP isthat psychotherapeutic effects are dependent on in-session emotional processing inthe form of rise in complex transference feelings that occurs when treatment resis-tance is challenged. Recent research indicates that an unlocking of the unconscious,a powerful emotional breakthrough achieved at a high rise in complex transferencefeelings, can potentially enhance ISTDP’s effectiveness. While ISTDP has a growingevidence base, most of the research conducted has used small samples and has testedtherapy delivered by expert therapists. The aims of this study were to evaluate theoverall effectiveness of ISTDP when delivered in a tertiary psychotherapy service, andto investigate if having an unlocking of the unconscious during therapy predictedenhanced treatment effectiveness.Methods. A total of 412 patients were included in the analyses. The average length oftreatment was 10.2 sessions (SD 13.3). Multilevel growth curve modeling was usedto evaluate treatment effectiveness and the association between unlocking the un-conscious and outcome. A number of control predictors including type of treatmentresistance were selected and included in the analyses. Outcome measures were theBrief Symptom Inventory (BSI) and the Inventory of Interpersonal Problems (IIP).About half of the patients in the study were treated by therapists in training and theother half by more experienced therapists.Results. Growth curve analyses using the full intention-to-treat sample revealedsignificant within-group effects of ISTDP on both the BSI and the IIP. Effect sizeswere large (>0.80). Unlocking the unconscious during therapy was associated withsignificantly larger treatment outcome. The relationship was further moderated bytype of treatment resistance.Conclusion. This study adds to the empirical base of Davanloo’s ISTDP withconfirmed treatment effectiveness in a large-scale patient sample when ISTDPwas delivered by therapists with a range of experience. Furthermore, emotional

How to cite this article Johansson et al. (2014), Davanloo’s Intensive Short-Term Dynamic Psychotherapy in a tertiary psychotherapyservice: overall effectiveness and association between unlocking the unconscious and outcome. PeerJ 2:e548; DOI 10.7717/peerj.548

mobilization in the form of unlocking the unconscious was confirmed as a processfactor enhancing the effectiveness of ISTDP.

Subjects Clinical Trials, Evidence Based Medicine, Psychiatry and PsychologyKeywords Psychotherapy, Psychodynamic psychotherapy, ISTDP, Effectiveness, Affect, Emotion

INTRODUCTIONMental disorders are common conditions that generate huge costs for society and cause a

great deal of suffering for the affected individuals and their families (Ustun, 1999; Kessler et

al., 2007). Several mental conditions such as depression, anxiety, personality disorders and

a range of medically unexplained symptoms are suggested to be linked to adverse childhood

experiences (ACE; Felitti et al., 1998; Edwards et al., 2003; Anda et al., 2006). Problems

arising from ACE are suggested to be byproducts of strong unprocessed emotions coupled

with deficits in capacity to regulate emotions (Schore, 2001; Schore, 2002; Anda et al., 2006).

Research indicates that several individuals with conditions linked to ACE are likely to

be treatment-resistant or to experience recurrences (Chartier, Walker & Naimark, 2010).

One consequence of this treatment resistance can be chronic illness and large system costs

(Nanni, Uher & Danese, 2012). Recently, there have been calls for the development and

evaluation of intensive and alternative treatments that address treatment resistance in these

patient populations (Nanni, Uher & Danese, 2012).

Intensive Short-Term Dynamic Psychotherapy (ISTDP; Davanloo, 1990; Davanloo,

2000; Davanloo, 2005; Abbass, Town & Driessen, 2012) is an emotion-focused psychody-

namic psychotherapy that explicitly addresses treatment resistance in somatic conditions,

mood, anxiety and personality disorders arising from ACE. Psychotherapeutic effects

in ISTDP are hypothesized to be dependent on in-session mobilization of emotional

processes in the form of rise in complex transference feelings, defined by co-occurring

increases in treatment resistance, unconscious anxiety, therapeutic alliance and experience

of feelings (Davanloo, 2005). A major unlocking of the unconscious is a powerful in-session

emotional breakthrough achieved at a high rise in complex transference feelings assumed

to take place when treatment resistance has been adequately challenged. During an

unlocking of the unconscious the patient experiences intense complex feelings towards

the therapist or another current figure, in which the experience is linked to feelings to past

figures and emotion-laden memories about painful feelings, situations and events from the

past, i.e., events related to adverse childhood experiences. A fundamental assumption in

Davanloo’s ISTDP is that the unlocking of the unconscious is associated with therapeutic

gains. Recent research from a sample of 89 patients, all treated by an experienced ISTDP

therapist, support Davanloo’s claim (Town, Abbass & Bernier, 2013). In addition, ISTDP

has been shown to be effective for a range of conditions (Abbass, Town & Driessen, 2012;

Town & Driessen, 2013) including patients who failed to respond to specialist medical,

surgical or psychiatric care (Baldoni, Baldaro & Trombini, 1995; Abbass, 2006; Abbass, Lovas

& Purdy, 2008; Abbass, Town & Bernier, 2013), or who used an unusually high amount

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 2/20

of emergency services (Abbass et al., 2009). However, a majority of existing studies have

included small samples and therapies delivered by expert therapists, and are thereby

limited in generalizability (Abbass, Town & Driessen, 2012).

The major aims of this study were to evaluate the effectiveness of ISTDP in a tertiary

psychotherapy service where patients had been referred from specialist care, and to study

if unlocking the unconscious was associated with outcome after controlling for potentially

confounding variables, including treatment resistance. The present study differs from most

previous research on ISTDP in that it is based on a large clinically representative sample of

patients treated by therapists with a range of experience and that it uses multilevel growth

curve techniques to model symptom change over time.

MATERIALS & METHODSThis study is reported in accordance with the CONSORT statement for clinical trials

(Schulz, Altman & Moher, 2010). The study is an evaluation of the effectiveness of a

treatment given in a tertiary care clinic and used anonymized data collected as part of

standard care. The project was reviewed and approved by the Capital District Health

Authority Research Ethics Board in Halifax, Nova Scotia (approval number 2007-050), and

is registered in Clinicaltrials.gov as identifier number NCT01924715.

Setting for treatment deliveryAll patients received treatment at the Centre for Emotions and Health located in Halifax,

Nova Scotia, Canada. The centre is a tertiary psychotherapeutic service linked to Dalhousie

University and located in the Queen Elizabeth II Health Science Centre in Halifax.

Furthermore, the centre is a teaching and research service specializing in assessing and

treating emotional contributors to medically unexplained symptoms, anxiety, depression

and personality disorders using ISTDP.

Participants and procedureParticipants in the study were collected from a large sample of patients referred to

the Centre for Emotions and Health between March 30, 1999 and March 30, 2007. A

substantial amount of patients referred were seen for an assessment meeting only. In

this study, we investigated outcome for all patients who received at least one session of

ISTDP after the initial assessment session (the trial therapy). As routine self-reported

outcome measures were only implemented part way through this 8 year period, only a

portion of the entire treated sample could be included in the effectiveness evaluation.

Hence, a further criteria for inclusion in this study was that the patient had a baseline

measurement of self-reported symptom distress (see below). The procedure described

below is illustrated in the CONSORT flowchart in Fig. 1. All participants in the study

were referred by professionals from various specialties, including emergency department,

family practice offices, medical-surgery and mental health. Patients referred to the Centre

were placed on a wait-list for a trial of therapy, i.e., an initial assessment session of ISTDP.

During trial therapy a psychodiagnostic evaluation was conducted which included an

assessment of type and degree of treatment resistance according to specified criteria. In

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 3/20

Figure 1 CONSORT flowchart. Abbreviations: ITT, intention-to-treat.

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 4/20

addition, baseline assessments of self-rated symptom distress and interpersonal problems

(regarding the previous two week period) were collected at the end of the trial session, at

the end of the session following the trial, and at treatment termination. Treatment was not

time-limited. Rather, termination was determined by response to treatment and agreed

upon by patient and therapist.

Intervention and therapistsIntensive Short-Term Dynamic PsychotherapyThe treatment used in this study was Intensive Short-Term Dynamic Psychotherapy

(ISTDP; Davanloo, 1990; Davanloo, 2000; Davanloo, 2005; Abbass, Town & Driessen, 2012).

ISTDP is a brief psychotherapy based on traditional psychodynamic principles, however,

with a strong focus on emotional mobilization and handling of in-session defenses against

experiencing of emotions (i.e., treatment resistance). Importantly, experiencing emotions

can include a range of experiences including emotional closeness with the therapist. The

first session in ISTDP, the trial therapy, is typically longer than the following sessions and

involves a psychodiagnostic evaluation, i.e., a thorough assessment of problems in relation

to emotional experience, how and to what degree the patient defends against emotions in

session and the patient’s capacity to tolerate anxiety (Abbass, Joffres & Ogrodniczuk, 2008).

The trial therapy also involves emotional experience of repressed feelings related to ACE

where possible. For a substantial amount of patients, the trial on its own brings symptom

relief and eliminates the need for further therapy (Abbass, Joffres & Ogrodniczuk, 2008).

ISTDP and treatment resistanceISTDP tailors the treatment process to different patient categories based on patients’

capacity to tolerate anxiety and work through emotions as they arise. Davanloo (2001) has

defined two spectra that help characterize patient functioning according to degree and

type of resistance. Psychoneurotic patients are patients with an intact psychic structure with

formal defenses they use in session. These patients do not experience cognitive perceptual

disruption and do not rely on primitive defenses such as projective identification. Fragile

patients, on the other hand, have unconscious anxiety manifest as cognitive perceptual

disruption (e.g., dissociation) and have access to primitive defenses at either a low,

moderate or high level of emotional activation (Davanloo, 2001). Such a pattern implies

that these patients have a less intact defensive structure. Hence, this is another type of

treatment resistance. ISTDP for psychoneurotic and fragile patients tends to be different.

For psychoneurotic patients, where patients can better tolerate emotional experiences,

defenses towards such experiences are explicitly challenged. Fragile patients require process

to build capacity to tolerate anxiety and emotions (Davanloo, 1990; Whittemore, 1996;

Abbass & Bechard, 2007). This latter format also applies to patients with severe depression

and somatic conditions such as conversion and irritable bowel syndrome (Davanloo, 2005).

Patients with psychotic disorders can also benefit from this capacity-building format of

ISTDP (A Abbass, D Bernier, S Kisely, JM Town & R Johansson, 2014, unpublished data;

Abbass, 2002). When working with ISTDP for psychotic patients the therapy is supportive

and devoid of any challenge to defenses. The therapy is facilitative of an emotionally active

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 5/20

learning where unconscious processes are studied and underscored toward mastering

emotions and developing better tolerance of anxiety. Thereafter, some of these unprocessed

emotions may be experienced to facilitate grieving of losses and resolution of internal

conflicts. Losses related to the illness and emotions around imposed treatments and

hospitalizations are also grieved (A Abbass, D Bernier, S Kisely, JM Town & R Johansson,

2014, unpublished data).

TherapistsTherapists were licensed health professionals and trainees learning ISTDP. One of the

therapists was a highly experienced ISTDP trainer and supervisor, considered an expert in

the field. All therapists were part of weekly small-group supervision led by the experienced

ISTDP trainer. Supervision included review of video recordings of treatment sessions

(Abbass, 2004). Furthermore, the therapists were provided technical literature on ISTDP

and attended weekly didactic courses.

Outcome measuresTreatment effectiveness was evaluated using the Brief Symptom Inventory (BSI; Derogatis

& Melisaratos, 1983) and the Inventory of Interpersonal Problems, 32 item version (IIP;

Horowitz et al., 1988). The Global Severity Index (GSI), derived using the procedures from

the BSI manual, was used as a measure of general symptom distress. For the IIP, the total

mean score was used as an overall measure of problems in relationships related to, for

example, self sacrificing and lack of assertiveness. Hence, this measures problems that are

assumed to be ameliorable with ISTDP. These measures were administered at baseline, at

the first meeting after the trial therapy session, and at treatment termination.

Rise in complex transference feelings and treatment resistanceWithin the framework of ISTDP, distinguishable phases that occur during mobilization

of unconscious processes have been established (Davanloo, 1990). These phases, the

degree of rise in complex transference feelings, aim to distinguish phases of mobilization

of unconscious emotional processes, defined by co-occurring increases in resistance,

unconscious anxiety, the experience of feelings and the unconscious therapeutic alliance.

According to Davanloo (2005), the phases have been replicated through repeated case series

data. The major unlocking of the unconscious is a state possible to reach at a high rise in

complex transference feelings (i.e., with a strong mobilization of unconscious processes)

after resistance has been systematically challenged. This state is defined as a passage of

intense complex feelings towards the therapist (or another current figure), in which a past

person’s image is transferred onto the current figure. ISTDP suggests this to be a passage of

complex feelings towards the past figure triggered by the complex feelings activated in the

therapy session. Typically this experience leads to emotion-laden memories about painful

feelings, situations and events from the past, i.e., events related to adverse childhood

experiences. In this state, the patient typically displays no resistance in the process and has

far less anxiety. Thereafter, the process of linking in-session resistance and avoided feelings

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 6/20

to past adverse experiences can proceed with few obstacles (Davanloo, 2005; Town, Abbass

& Bernier, 2013).

For ratings of rise in complex transference feelings in this study, we used a quantitative

coding system with categories as follows: (1) low rise in complex transference feelings,

(2) high rise in complex transference feelings, (3) partial unlocking of the unconscious,

(4) major unlocking of the unconscious, and (5) extended major unlocking of the

unconscious. Details of these phases can be found in Davanloo’s writings (Davanloo,

2001; Davanloo, 2005). As one of the primary aims of this study was to investigate whether

having a major unlocking of the unconscious (categories 4 and 5) predicted treatment

outcome (as suggested by Town, Abbass & Bernier (2013)), we included a binary variable

that captured this (1 = “did have a major unlocking of the unconscious during therapy”, 0

= “did not have a major unlocking of the unconscious during therapy”).

According to Davanloo (1990), Davanloo (2001) and Davanloo (2005), rise in complex

transference feelings are dependent on the type and degree of patient resistance operating

at any given point during the psychotherapeutic encounter. Patient resistance is defined as

any unconscious or previously unconscious defense operating in the therapy relationship.

Based on case-series data from several hundred patients, Davanloo (2001) and Davanloo

(2005) established operationally defined patient categories of treatment resistance based on

the observation of in-session use of defenses and anxiety discharge patterns. As described

above, a patient is considered fragile when primitive defenses and cognitive perceptual

disruption are prominent features and psychoneurotic when not. This is the basis for how

Davanloo (1990) established two types of resistance that each is a spectrum of degree of

resistance. Davanloo (2001) named these the spectrum of patients with psychoneurotic

disorders and the spectrum of patients with fragile character structure. In this particular

study, we used a coding of treatment resistance as follows: (1) low resistance, (2) moderate

resistance, (3) high resistance, (4) fragile, and (5) psychotic. As the purpose of this

particular study was to control for type of defensive structure, we included a binary

variable that described this (0 = “low to high resistance”, 1 = “fragile or psychotic”).

Coding of treatment resistance and rise in complex transference feelings was conducted

during supervision by the experienced ISTDP supervisor using review of video recordings

of treatment.

Statistical analysesThe study had an open design in that no control group was used. A set of analyses were

carried out that focused both on the within-group effects of treatment on outcome (time

effects) and on whether having an unlocking of the unconscious during therapy predicted

these effects. These analyses were addressed with growth curve modeling using SPSS

version 21 (SPSS, Inc., Chicago, IL) and followed the procedures described by Singer &

Willett (2003).

A series of growth curve models of the trajectories of the BSI and the IIP were generated

and tested. First, unconditional growth models were estimated for both variables to

examine the average growth over the course of treatment.

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The equations for the unconditional growth models estimating the effects of therapy

over time were as follows:

Level-1 Model:

Yij = π0i + π1i × TIMEij + εij.

Level-2 Model:

Intercept: π0i = γ00 + ζ0i

Slope: π1i = γ10 + ζ1i

εij ∼ N(0,σ 2ε ),ζ0i ∼ N(0,σ 2

0 ),ζ1i ∼ N(0,σ 21 ).

The intercept and the slope were allowed to covary. Error terms across time were

assumed to be uncorrelated. Time was coded 0 for baseline, 0.25 for post-trial assessment

and 1 for termination. Length of therapy and waiting time from trial therapy to treatment

start varied. The codings of time were based on an estimation that the average waiting time

from trial therapy to post-trial assessment was a third of the time of the length of an average

full treatment course.

Second, conditional growth models were estimated to examine whether the growth

trajectory of the outcomes (BSI and IIP) differed as a function of having a major unlocking

of the unconscious. Unlocking of the unconscious was included as a time-invariant

binary coded predictor. This variable reflected whether a patient had a major unlocking

of the unconscious anytime during therapy. Patient gender, age, type of treatment

resistance, total number of sessions and therapist experience were investigated as potential

control predictors. Number of sessions was log10-transformed to improve normality. To

determine if a control predictor was to be included in the growth curve models, descriptive

analyses were carried out to investigate if there were any BSI or IIP differences at any time

point due to the predictor in question. If a significant difference was present, the predictor

was included in the analyses. Independent t-tests were used to make a decision on binary

predictors and one-way ANOVAs were used for continuous predictors converted into

quartiles.

Our analytical approach made use of all available data, making this an intention-to-treat

analysis. Full information maximum likelihood estimation was used. This form of estima-

tion provides unbiased estimates under the less restrictive assumption of data missing at

random (MAR; Mallinckrodt, Clark & David, 2001), which allows the probability of data

being missing to be dependent of both outcome variables (e.g., symptom level as measured

by the BSI and the IIP) and predictors (Little & Rubin, 2002). To take missing data further

into account, we performed additional analyses where informativeness of missing data

patterns were investigated as potential confounding factors (Little & Wang, 1996; Hedeker

& Gibbons, 1997). As formal dropout was not recorded, we treated post-treatment data

missing due to dropout and data missing for other reasons as equivalent.

Within-group effect sizes (Cohen’s d) were calculated by dividing the pre-post

differences in observed means by the pooled standard deviations (Borenstein et al., 2011).

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 8/20

RESULTSBaseline characteristics and enrollmentThere were 1010 participants referred to the clinic during the study. Of those referred,

500 had a trial therapy and did also complete a baseline assessment. Out of these, 412

patients had at least one session after the trial and were then included in the effectiveness

evaluation. These patients averaged 41.5 years of age (SD 12.7, data on age missing on

34% of cases) and 59.0% were female. The most common clinically derived DSM-IV

diagnoses among the 412 included participants were somatoform disorder (58.7%),

anxiety disorders (53.4%), cluster B and C personality disorder (18.2% and 36.7%), and

major depression (39.3%). Furthermore, 45.6% had chronic or recurrent headache, 31.3%

had pain disorder, 23.5% had irritable bowel syndrome and 14.1% had fibromyalgia. These

patients had an average treatment duration of 10.2 sessions (SD 13.3, range 2–100, median

5). A complete description of the flow of participants is given in Fig. 1.

Data attritionThere were 118 participants who had only one treatment session after the trial therapy. For

these, the post-trial assessment was the last measurement. Out of these 118 participants,

83 and 72 completed the BSI and the IIP at post-trial, respectively (i.e., 29.7% and 39.0%

missing). Among the 294 participants who had more than two sessions, 168 and 142

participants completed the BSI and the IIP at termination, respectively (i.e., 42.9% and

51.7% missing). Hence, the total attrition at the last assessment point was 39.1% for the

BSI and 48.1% for the IIP. This is further illustrated in the flowchart in Fig. 1.

Therapists and trainingTwo hundred and twenty cases (53.4%) were treated by 4 graduated psychiatrists or 1

psychologist with a mean of 1374.6 (SD 817.6) total training hours (including didactic

training and group videotape supervision). Out of these, 115 cases were treated by a

psychiatrist who was considered an expert in ISTDP, with over 2000 h of total training. One

hundred and ninety-two cases (46.6%) were treated by 43 trainees with a mean of 229.6

(SD 208.9) total training hours. This latter group was comprised of psychiatry residents

(n = 29), and a mix of other students and professionals in training (n = 14).

Treatment resistance and major unlocking of the unconsciousOf the 412 included participants, 408 (99.0%) had data on treatment resistance. Out of

these, 289 participants (70.8%) met criteria for psychoneurotic and 119 (29.2%) were

fragile (n = 86) or psychotic (n = 33). Furthermore, 153 out of 411 participants (37.2%)

had at least one major unlocking of the unconscious throughout treatment (data on

unlocking missing for one patient).

Effects of time (Unconditional growth models)BSIResults from the unconditional growth model for BSI indicated that there was significant

variance in the intercept (symptom level at baseline) and in the slope (rate of decrease of

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Table 1 Means, SDs and effect sizes (Cohen’s d) for the Brief Symptom Inventory (BSI) and theInventory of Interpersonal Problems (IIP).

Baseline (SD) N Termination (SD) N Mean difference (SD) N Effect size (95% CI)

BSI 1.60 (0.75) 412 0.92 (0.77) 168 0.67 (0.69) 168 0.87 [0.71–1.03]

IIP 1.51 (0.64) 390 0.99 (0.68) 144 0.53 (0.63) 142 0.83 [0.64–1.02]

BSI scores over time). The mean BSI trajectory was estimated to start at 1.58 at baseline

and to slope downward at a rate of 0.70 BSI units over the course of treatment. The

covariance between the intercept and the slope was −0.10, indicating that patients who

started with higher BSI scores at baseline had steeper BSI slope trajectories. Effect size

(based on observed means) was Cohen’s d = 0.87 95% CI [0.71–1.03], indicating a large

effect of treatment over time. Means and standard deviations for the raw BSI scores are

presented in Table 1.

IIPThe unconditional growth model used to model IIP indicated significant variance in the

intercept and the slope. The covariance between the intercept and the slope was −0.07

(p = .07), once again indicating that starting at higher baseline IIP resulted in steeper rate

of change. The mean IIP trajectory was estimated to start at 1.50 at baseline and to slope

downward at a rate of 0.59 IIP units over the whole treatment. There was a large effect size

Cohen’s d = 0.83 95% CI [0.64–1.02] over time (based on observed means). Means and

standard deviations for the IIP can be found in Table 1.

Associations of unlocking the unconscious with outcome (Condi-tional growth models)Control predictorsType of treatment resistance, therapist experience, patient gender, patient age, and

the logarithm of number of treatment sessions were investigated as potential control

predictors of outcome. Therapist experience was investigated both by comparing trainees

to non-trainees, and by comparing the outcomes of the ISTDP expert to the other

therapists. Descriptive analyses of the predictors at all time points revealed that there

were BSI differences at baseline with fragile and psychotic patients having larger symptom

severity than psychoneurotic patients (independent t-test, t(406) = 4.3, p < .001), with a

similar trend on the IIP at baseline (independent t(384) = 1.9, p = .06) and at post-trial

(independent t(221) = 1.8, p = .08). Furthermore, on IIP there was a difference at

termination depending on therapist experience, with the 43 trainees having worse outcome

than the six non-trainees (independent t(142) = 2.3, p < .05) and the expert having better

outcome than the other 48 therapists (independent t(142) = 2.6, p < .05). The ANOVA

investigating differences due to number of sessions (log) revealed a difference on the IIP

at post-trial (F(3, 204) = 3.26, p < 0.05). An inspection of the post-trial IIP raw scores

indicated that participants who only took part of the trial therapy and the follow-up

meeting had lower IIP scores at this time point than those who continued with further

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 10/20

therapy. This difference was significant (independent t(222) = 2.46, p < .05). No other

differences due to number of sessions were found at any other time point on neither the

BSI nor the IIP (all F’s < 1.98, all p’s > 0.11). No gender differences at any time point were

found (all t’s < 1.5, all p’s > .14). Similarly, no differences due to age were found (all F’s

< 1.82, all p’s > .14). Based on these findings, we decided to include type of resistance,

trainee status, expertise and number of sessions (log) as control predictors.

BSIIn an uncontrolled conditional growth model, the variable that measured whether the

patient had a major unlocking of the unconscious during therapy (called UNLOCKING

in this section) was added at Level 2 as a time-invariant predictor in interaction with

the initial status (intercept) and in interaction with time. The latter interaction term was

added to determine if, over time, UNLOCKING significantly interacted with the BSI

slope, i.e., predicted symptom change during treatment. At this stage of the analysis, the

UNLOCKING by time was close to significant (p = .08) in the model.

The next step carried out was to determine if this association between UNLOCKING

and BSI change was still present after accounting for type of treatment resistance, trainee

status, expertise and the logarithm of number of treatment sessions (called RESISTANCE,

TRAINEE, EXPERT and log(SESSIONS) in this section). Hence, a controlled conditional

growth model was carried out. RESISTANCE, TRAINEE, EXPERT and log(SESSIONS)

were added as time-invariant predictors in interaction terms with baseline BSI (the

intercept) and BSI change (slope). The RESISTANCE and EXPERT by intercept and time

were significant, and therefore kept in the model. However, TRAINEE and log(SESSIONS)

were not significant neither in interaction with the intercept nor with the slope and

therefore left out of the model. Finally, we added information on missingness from the

post-trial and post-treatment assessments in interaction with the intercept and with the

slope to investigate if data missingness was related to outcome (Little & Wang, 1996;

Hedeker & Gibbons, 1997). Neither of these interactions were significant and therefore

information on missing data was removed from the model. In the final model (details in

Table 2), the UNLOCKING by time interaction was significant (p < .05). Estimated means

from this model are illustrated in Fig. 2. The equations for the final BSI model were as

follows:

Level-1 Model:

Yij = π0i + π1i × TIMEij + εij

Level-2 Model:

Intercept: π0i = γ00 + γ01 × UNLOCKINGi + γ02

×RESISTANCEi + γ03 × EXPERTi + ζ0i

Slope: π1i = γ10 + γ11 × UNLOCKINGi + γ12 × RESISTANCEi + γ13 × EXPERTi + ζ1i

εij ∼ N(0,σ 2ε ),ζ0i ∼ N(0,σ 2

0 ),ζ1i ∼ N(0,σ 21 ).

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 11/20

Figure 2 BSI and IIP scores. Estimated means of the Brief Symptom Inventory and the Inventory ofInterpersonal Problems at baseline, post-trial and at treatment termination.

Table 2 Growth models estimating trajectories of change in Brief Symptom Inventory (BSI) and Inventory of Interpersonal Problems (IIP)from baseline to treatment termination.

BSI IIP

Parameter Unconditionalgrowth model

Final controlledgrowth model

Unconditionalgrowth model

Final controlledgrowth model

Fixed effects

Initial status, π0i Intercept γ00 1.58*** 1.47*** 1.50*** 1.45***

Unlocking γ01 0.04 0.03

Resistance γ02 0.37*** 0.15*

Expertise γ03 −0.04

Rate of change, π1i Intercept γ10 −0.70***−0.46***

−0.59***−0.50***

Unlocking γ11 −0.21*−0.20*

Resistance γ12 −0.22*

Expertise γ13 −0.22*

Variance components

Level 1 Within-person σ 2ε 0.16*** 0.15*** 0.13*** 0.13***

Level 2 In initial status σ 20 0.42*** 0.40*** 0.31*** 0.31***

In rate of change σ 21 0.17** 0.15** 0.14** 0.13*

Covariance σ01 −0.10*−0.08*

−0.07tr−0.06

Notes.tr, trend.

* p < .05.** p < .01.

*** p < .001.

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 12/20

IIPInitially UNLOCKING was added as a predictor and was close to significant (p = .07) in

interaction with time. RESISTANCE was added and was significant in interaction with the

intercept, but not with the slope. Hence, the RESISTANCE times slope interaction was left

out of the final model. Neither TRAINEE, EXPERT nor log(SESSIONS) were significant

in interaction with the intercept or the slope, and therefore not included in the model. In

the final model, the UNLOCKING by time interaction was significant (p < .05). As in the

BSI model, information on missingness was not significant and was therefore not included.

Results from the IIP model are illustrated in Fig. 2. Details of the final model can be found

in Table 2 and in the equations below:

Level-1 Model:

Yij = π0i + π1i × TIMEij + εij

Level-2 Model:

Intercept: π0i = γ00 + γ01 × UNLOCKINGi + γ02 × RESISTANCEi + ζ0i

Slope: π1i = γ10 + γ11 × UNLOCKINGi + ζ1i

εij ∼ N(0,σ 2ε ),ζ0i ∼ N(0,σ 2

0 ),ζ1i ∼ N(0,σ 21 ).

DISCUSSIONIn this paper, we have established the effectiveness of Davanloo’s Intensive Short-Term

Dynamic Psychotherapy when delivered by a range of therapists in a clinically representa-

tive setting to a large number of patients. Importantly, the present study was carried out in

a tertiary care clinic, which is assumed to have implied a more treatment-resistant patient

sample than those present in standard clinics. This study adds to the overall evidence base

of ISTDP in particular, but also to that of psychodynamic psychotherapy in general. In a

recent meta-analysis on randomized controlled trials of psychodynamic psychotherapy

(Town et al., 2012a), the overall within-group effect size was estimated to Cohen’s

d = 1.01 95% CI [0.86–1.16]. Furthermore, a study evaluating the overall effectiveness

of psychotherapy for depression among 5,704 clinical patients in a managed care setting

(Minami et al., 2008) estimated the effect size to be d = 0.75 95% CI [0.72–0.77]. Hence,

the effects observed in this study (effect sizes Cohen’s d = 0.87 (95% CI [0.71–1.03] and

d = 0.83 95% CI [0.64–1.02] for the BSI and the IIP, respectively), seem to be comparable

both to effects of psychodynamic psychotherapy when provided in RCTs and to that of

psychotherapy in general when provided in clinical practice.

In this study, we also showed that a major unlocking of the unconscious during therapy

predicted better treatment outcome. This result validates a fundamental assertion in

Davanloo’s ISTDP and is to our knowledge the first study to systematically reproduce those

assertions in a large-scale patient sample (Town, Abbass & Bernier, 2013). Moreover, this

finding is in line with research suggesting that affective experience during psychodynamic

psychotherapy may enhance treatment effectiveness (Whelton, 2004; Diener, Hilsenroth

& Weinberger, 2007; Diener & Hilsenroth, 2009; Salvadori, 2010). Importantly, strong

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 13/20

emotional breakthroughs in ISTDP are assumed to be dependent on the therapist’s

systematic challenge to resistance in session. Hence, our findings in this paper are likely

to parallel recent research that have highlighted a relationship between affective arousal

and preceding active therapist confrontation (Town et al., 2012b).

In the investigation of the associations of unlocking with outcome, we included a

number of control predictors including type of treatment resistance. The association of

type of treatment resistance with outcome can be interpreted as a separate effect, after

controlling for the main predictor of interest (unlocking the unconscious). Patients

classified as fragile or psychotic had more symptom severity at baseline than those who

were psychoneurotic. This is in line with psychodynamic theory suggesting that individuals

with access to primitive defenses (fragile or psychotic) have been exposed to more adverse

and/or persistent childhood experiences: this on its own is known to be associated with

higher symptom severity in later life (Felitti et al., 1998; Edwards et al., 2003). Furthermore,

we found that fragile patients had (compared to psychoneurotic patients) steeper rate of

change on the BSI, while there was no such difference in slope on the IIP. This suggests

that, to understand the larger degree of change in reduced symptom distress seen in

fragile patients, it may be necessary to look beyond the concept of achieving a major

unlocking of the unconscious to other therapeutic variables. As described above, ISTDP

for fragile patients typically involves building capacity for tolerating emotional experiences

(Davanloo, 1990; Whittemore, 1996; Abbass & Bechard, 2007). Hence, results from this

study could indicate that this capacity-building format may be a key intervention when

working with patients with primitive defenses, character pathology and with a high

symptom burden. Furthermore, we replicated previous findings showing that the rate

of change on the IIP is associated with unlocking the unconscious, but not with any other

predictor (Town, Abbass & Bernier, 2013). Given the fact that change on the IIP may reflect

character change rather than symptom change, the typical treatment course in this study

(median 5 sessions, 10.2 on average) may not have been long enough to achieve major

changes on the IIP. Thus, if treatment courses had been longer, we could possibly have

expected a larger variation among IIP slopes, which then potentially could be explained

by other predictors than unlocking the unconscious. This could parallel the claim by

Davanloo that for major character change to take place, 20–40 sessions of ISTDP may be

needed for psychoneurotic patients and 60–80 for those with fragile character structure

(Davanloo, 2005).

Whether experienced therapists perform better than less experienced is a debated topic

in the psychotherapy research community, with limited literature suggesting that more

training enhance treatment effectiveness (Hattie, Sharpley & Rogers, 1984; Wampold &

Brown, 2005). This is in line with our findings that the group of professional therapists (vs.

trainees) with far more training hours did not seem to conduct more effective treatments.

It also parallels previous research on the effectiveness of ISTDP when carried out by

psychiatry residents that indicated reductions in both symptoms and health care costs

(Abbass, 2004; Abbass et al., 2013). However, we found that a single therapist, considered

an expert in ISTDP, had better outcomes than the other therapists, on one of the outcome

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 14/20

measures. This is indeed interesting as expertise in psychotherapy is largely unexplored

(Tracey et al., 2014). Further research on expert performance in ISTDP is warranted

based on these findings. To extend the current findings, this may include examination

of therapists’ competence as measured by the quality of the unlocking of the unconscious.

Strengths of this study include that the treatment was tested for a large-scale sample of

412 patients, that therapists were trained and supervised by a highly experienced ISTDP

teacher, and that data analyses were conducted using advanced statistical methods capable

of making use of all available data. A further strength is that several elements contribute

to the generalizability of the findings from this study: the treatment was provided in

a clinically representative setting by a large number of therapists with different levels

of experience, all patients were recruited by referral from professionals rather than

advertisement, and very broad selection criteria were applied that allowed a mixed sample

of patients to be included.

However, there are limitations of this research that need to be addressed. First, a

substantial number of patients did not have a post-treatment assessment (missing because

of dropout or other reasons, 39.1% on the BSI, 48.1% on the IIP). We addressed this

limitation by using data-analytic procedures that have been shown to be valid under the

assumption that the data was missing at random (MAR). This allows the probability of

data being missing to be dependent upon both outcome variables (e.g., symptom severity)

and predictors (Little & Rubin, 2002). Furthermore, we conducted additional pattern

mixture models to take data missingness into account (Little & Wang, 1996; Hedeker &

Gibbons, 1997). Despite the use of these data-analytic procedures, we cannot exclude the

possibility that the results from this study have been affected by the amount of missing

data. The actual rate of dropout in this study was difficult to determine also because

many patients came from far away and only attended a few sessions for travel reasons.

Importantly though, meta-analytic estimations of the number of dropouts have found

similar rates as in this study. An investigation of 125 psychotherapy outcome studies

estimated the mean dropout rate to 46.9% (Wierzbicki & Pekarik, 1993). More recently,

a meta-analysis of 34 non-randomized effectiveness studies on outpatient cognitive

behavioral therapy for depression found that 42.0% of patients who received individual

therapy dropped out (Hans & Hiller, 2013). Our rates of missing data and/or dropout

also parallel a recent large-scale effectiveness evaluation of psychodynamic psychotherapy

for depression in which 45.2% of the participants dropped out or were lost to assessment

(Driessen et al., 2013). A second limitation in this study was the fact that the ratings of

rise in the complex transference feelings and degree and type of treatment resistance

were conducted using non-validated instruments. Measurements of these constructs

in this study were carried out by a highly experienced ISTDP clinician and teacher. We

have because of the experience of the coder assumed adequate validity and reliability of

these measurements. However, this procedure might have caused a measurement bias

due to the theoretical orientation of the ISTDP teacher. In conclusion, this limitation

highlights the need to develop psychometrically sound and reproducible procedures

to measure the constructs proposed by Davanloo (1990), Davanloo (2000), Davanloo

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 15/20

(2001) and Davanloo (2005). Third, the results in this study on unlocking in relation

to outcome are correlational, i.e., we have not established a causal effect. Hence, we

cannot exclude a possible reversed causal effect, that symptom relief on its own resulted

in emotional breakthroughs. While we consider this as unlikely due to the fact that a

major unlocking is assumed to be the result of the breakdown of treatment resistance

after systematic challenge, we acknowledge the need for future research that establish a

causal relationship between outcome and in-session events in ISTDP. Fourth, data from

self-report measures was collected only at three time points instead of weekly assessments.

While a weekly collection might not have been possible to carry out within the current

routine care setting, it would have contributed to a better estimate of the treatment effect

over time. A related concern is that the research project did not record the exact times from

baseline to post-trial and from post-trial to termination. Instead, estimated averages for

these time periods times were used. We acknowledge this lack of a more precise coding

of time as a limitation of the study. A final limitation is that the lack of control condition

and the non-randomized effectiveness design of this study did not permit us to control

for gains due to time passing (e.g., spontaneous gains and gains from other treatments

received). Nor was there any extended baseline assessment phase that could have been

used to estimate the effect of time before treatment started. Hence, we cannot exclude the

possibility that the treatment effects observed in this study were due to other factors than

the treatment received. However, this is unlikely given the short treatment duration and the

likely chronicity of patient problems referred to this service.

Based on the findings from this study, further research on ISTDP is warranted. We see a

continued need for systematic investigation of the efficacy of ISTDP for specific diagnostic

groups using randomized controlled trials. Such research could also include assessments

of in-session events such as rise in complex transference feelings, that would enable more

detailed examinations of the relation between events such as the major unlocking of the

unconscious and outcome. Furthermore, standardized ratings of rise in the complex

transference feelings and type and degree of resistance should be developed for future

research on ISTDP, to enable further knowledge of the mechanisms of change in ISTDP. A

guide for such ratings is in development (JM Town & A Abbass, 2014, unpublished data).

CONCLUSIONSThis study shows that Davanloo’s Intensive Short-Term Dynamic Psychotherapy is an

effective treatment when carried out in tertiary care, when delivered by therapists with

a range of experience. Furthermore, this study provides support for the key assumption

in Davanloo’s ISTDP in that unlocking the unconscious is associated with enhanced

treatment outcome. Further research on the effectiveness of ISTDP and its working

mechanisms is warranted.

ACKNOWLEDGEMENTSThis paper is dedicated to Dr. Habib Davanloo who we believe has enriched the field

of psychotherapy by his research and by the development of ISTDP. Furthermore, we

extend our thanks to Professor Gerhard Andersson of Linkoping University, Sweden, who

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 16/20

provided financial support for the first author of this study (RJ) during the finalization of

this project.

ADDITIONAL INFORMATION AND DECLARATIONS

FundingThe research project was supported by the Department of Psychiatry at Dalhousie

University and the Department of Health and Wellness for the province of Nova Scotia.

The funders had no role in study design, data collection and analysis, decision to publish,

or preparation of the manuscript.

Grant DisclosuresThe following grant information was disclosed by the authors:

Department of Psychiatry, Dalhousie University.

Department of Health and Wellness for the province of Nova Scotia.

Competing InterestsThe authors declare there are no competing interests.

Author Contributions• Robert Johansson conceived and designed the experiments, analyzed the data, wrote the

paper, prepared figures and/or tables.

• Joel M. Town conceived and designed the experiments, analyzed the data, wrote the

paper.

• Allan Abbass conceived and designed the experiments, performed the experiments,

analyzed the data, wrote the paper.

Clinical Trial EthicsThe following information was supplied relating to ethical approvals (i.e., approving body

and any reference numbers):

The Capital District Health Authority Research Ethics Board (Halifax, Nova Scotia)

approval: 2007-050. The study is an evaluation of the effectiveness of a treatment given in a

tertiary care clinic and used anonymized data collected as part of standard care.

Clinical Trial RegistrationThe following information was supplied regarding Clinical Trial registration:

ClinicalTrials.gov: NCT01924715.

Supplemental InformationSupplemental information for this article can be found online at http://dx.doi.org/

10.7717/peerj.548#supplemental-information.

Johansson et al. (2014), PeerJ, DOI 10.7717/peerj.548 17/20

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